This project has been composed of the following studies: (1) An intensive multi-disciplinary study of a family with MZ quadruplets, (daughters) concordant as to schizophrenia but discordant as to severity and outcome; (2) Studies of Danish Adoptees and their biological and adoptive families; (3) A study of children (of schizophrenic and control parents) reared in town or kibbutz in Israel. We maintain contact with the quadruplets but have not pursued active studies with them during the past three years. The Danish adoptees are of continuing interest to us and we are preparing additional reports on factors involved in their psychiatric outcome. The Israeli children are the subject of intensive research efforts and we are currently conducting further behavioral and biological studies with them.